Display does not seem to be blanking in-between painting frames whilst animating to the final Workspace Switcher view.
Hit-testing for windows is broken.
See attached screenshot of Workspace Switcher shown with resolutions 1366x768 (laptop) and 1440x900 (monitor).

In the short term, the rendering and hit-test issues need to be fixed.

Hi Tim,
Sorry, by window hit testing I mean identifying the window under the mouse cursor when starting a drag. As of Precise (dev branch) + Unity 5.2.0 this is working correctly now.
However, the rendering is still not correct: the background is now being blanked for each frame of the transition animation, but the workspaces on the second display are not positioned correctly. See image attached for 2 displays: 1366x768 and 1440x900.

Please see #949502. The culprit is the "expo" plugin in the compiz main plugins. I looked around the code, but it's very messy. Expo has various modes, and they're all mixed together and in spaghetti fashion. It's not easy to determine how positioning and scaling is supposed to work. I'll take another look at it if I got the time.

Thank you for taking the time to report this bug. We have tried to recreate this on the latest release of Ubuntu and cannot reproduce it. This bug is being marked as Invalid. If you believe the problem to still exist in the latest version of Ubuntu please comment on why that is the case and change the bug status to NEW.